Providing highly precise dosing

The presence of dirt or lint in paper manufacturing has a major influence on the quality of recycled paper. Tokyo-based Maintech Co. Ltd. specializes in providing solutions to prevent this problem. The company’s Mist Runner paper dust and dirt prevention equipment now uses the Grundfos DME series of digital diaphragm dosing pumps on an OEM basis.

In the production of paper, water is removed from the paper with a dryer; a cast drums roughly one meter in diameter. In the production of recycle paper, the fiber, ink or glues from old paper can adhere and burn into the surface of the dryer, causing depression or holes in the finished paper. To prevent this, the Mist Runner sprays a chemical dirt preventative onto the dryer.

With some of our competitor’s products, chemical use can be measured in tons per month. For Maintech products, the units are more likely to be 200 to 400 kilograms per month per unit. Each application is only about five to ten milliliters per minute. It is difficult to get such a small discharge volume with a regular pump, so as we looked at the kinds of pumps available we discovered that dosing pumps would be ideal for the job. Maintech first used the pump of another company, but soon found out that they often had to perform calibrations. Because the pump used a dial setup system to establish the desired volume, Maintech had to use a different exchange table for the calculation on each dosing pump. This also made control in the workplace complicated as well. As we were trying to think of a better way of doing things, someone from one of the paper manufacturers introduces us to the Grundfos DME series.

When Maintech tried out the DME series, they soon found a number of advantages. Calibration only had to be performed once, there were no errors in the output volume thanks to the digital dosing display, and that volume as small as one millimeter per minute could be handled. These features exactly met the needs of the Mist Runner, which is adjusted to use exactly the right volume of chemical for each customer. Because of this Maintech began the introduction of the DME series in the Mist Runner in 2002.

The fact that one pump model has the ability to cover many different output volumes was a major advantage. According to Maintech, the pumps used earlier had to use completely different pumps for different volumes. The size of the pump also varied with each model, so they had problems fitting them into their machines. But with the DME 2-18 that Maintech is currently using, they can cover most of the needs of our customers with the one pump model.